The present invention relates to a shut-off solenoid valve of the circuit defined by a solenoid valve system.
The present invention further relates to a solenoid valve system comprising said circuit shut-off solenoid valve.
The term “solenoid valve system” indicates a set of two or more solenoid valves assembled on one or more bases mutually connected to form an assembly, which assembly in turn is connected to at least one head element or module.
In the jargon of the sector, such a solenoid valve system is generally indicated as “solenoid valve island” or “solenoid valve battery”.
In more detail, a solenoid valve system comprises:
two or more solenoid valves,
one or more bases, generally of the modular type, which are removably fastened to each other,
at least one head element or module connected and fastened to an end of the base or of the assembly of bases.
Each solenoid valve is generally of the spool type comprising:
a body, in which a plurality of mouths is obtained within which passes the flows of the pressurised fluid (air); the mouths comprise, in general, at least one feeding mouth, i.e. a mouth that has to be connected to the supply of pressurised fluid, at least one utilisation or outlet mouth, i.e. a mouth through which the pressurised fluid is sent to another apparatus, and at least one discharge mouth, i.e. a mouth from which the pressurised fluid, after it was utilised, is discharged or is returned into the atmosphere;
a movable element generally consisting of a spool-type slider or piston, which is slidably housed in a cylindrical seat obtained in the body and is configured to connected selectively to each other the various mouths, forcing the flow of the pressurised fluid to follow determined paths;
a plurality of gaskets interposed between the movable element and the body to assure fluid tightness and selectively isolating the mouths which, in each of the positions assumed by the distributor, must not be passed through by the flow of the pressurised fluid;
an actuation device or pilot command, which is generally of the electrical or electro-pneumatic type, which drives, directly or indirectly, the movement of the movable element to switch the distributor from the resting position to at least one working position; generally, the pilot command device consists of a combined command by means of a solenoid and pilot distributor and comprises a pneumatic actuator (for example a piston integral with the movable element) arranged to directly move the movable element and an electropilot consisting of a solenoid which, as a result of energisation and de-energisation, moves a core that opens and closes ducts that feed and discharge compressed air for the driving of the pneumatic actuator;
a repositioning device, for repositioning the movable element and, hence, the switching of the distributor from at least one working position to the resting position; the repositioning device can be external (pneumatic, electrical, electro-pneumatic) or internal (pneumatic or mechanical).
The solenoid valves can comprise one or more (generally two) spool distributors housed in the same body. Spool distributors can be of one of the types that, according to the unified classification, is classified, by way of example, as “3/2”, “5/2” or “5/3”.
Each base consists of a body in which are obtained one or more housings, each of which is configured to receive a respective solenoid valve and is provided with ducts for the passage of pressurised fluid that are connected with the corresponding mouths of the respective solenoid valve. In addition, in the base are defined the feeding and discharge ducts of the pressurised fluid which command the pneumatic actuators acting on the movable element of each solenoid valve.
Each housing obtained in the base is provided with: at least one feeding duct, at least one outlet or delivery duct and at least a discharge duct, which are connected respectively with the at least one feeding mouth, the at least one utilisation or outlet mouth and the at least one discharge mouth of the respective solenoid valve.
The base or, if the base is divided in two or more sections, each of which section operates at a different pressure and is provided with a respective feeding and discharge module, each section or portion thereof is then traversed by:
at least one main feeding duct that joins or otherwise defines the at least one feeding duct of each individual housing, the main feeding duct of the base (or of each section thereof) is a common duct that serves all the housings of the base (or of each section thereof),
at least one main discharge duct that joins or otherwise defines the at least one discharge duct of each individual housing, the main discharge duct of the base (or of each section thereof) is a common duct that serves all the housings of the base (or of each section thereof).
The at least one outlet or delivery duct of each housing of the base, instead, is distinct and separate from the outlet or delivery ducts of the remaining housings obtained in the base (or of each section thereof) and ends in a respective delivery opening that is accessible from the exterior of the base and that is connectable to a respective user (for example a pneumatic actuator) slaved to the corresponding solenoid valve.
The base is then provided with an electric or electronic circuit (for example an electronic board) and of related connecting means for the electric connection with the devices for the electric or electropneumatic actuation and/or repositioning of each solenoid valve, the connecting means branching off at each housing of the base.
Each solenoid valve is removably fastened to the base with known fastening members, e.g. of the screw type.
The bases are generally modular and can be mutually coupled and fastened removably with known fastening members, for example tie rods.
The head or intermediate element or module (i.e. local to each base section), or the head or intermediate feeding and discharge element or module, comprises a body in which are obtained:
at least a first joining duct that joins, at one end, with the at least one main feeding duct of the base (or of the corresponding base section) and which, at the opposite end, can be joined with a source of pressurised fluid,
at least a second joining duct that joins, at one end, with the at least one main discharge duct of the base (or of the corresponding base section) and that, at the opposite end, ends in a discharge opening,
an electric or electronic input module provided with at least one input connector, which is able to receive command signals imparted from outside the solenoid valve system, and an output connector, which is connectable to the corresponding input connector of the electric or electronic circuit of the base to transmit the command signals to it.
If the base is modular, each base module comprises an input connector and an output connector, coupleable respectively with the output connector of the head element or of the previous base module and with the input connector of the subsequent base module for the transmission of the command signals from the electric or electronic input module to the electric or electronic circuits of the various base modules.
The solenoid valve system can be completed by an end element positioned at the end of the base that is opposite to the one connected to the head element.
Known solenoid valve systems are for example described in WO2017/017650A1, WO2017/017653A1 and WO2017/017656A1.
FIG. 1 is an exploded view of a solenoid valve system according to the prior art; FIG. 2 shows a section of the solenoid valve system of FIG. 1 in which the solenoid valve comprises two “3/2” spool distributors normally closed housed in the same body; FIG. 3 schematically shows the pneumatic circuit of the solenoid valve system of FIG. 1.
With reference to these figures, the numeral 100 indicates a solenoid valve system comprising a modular base formed by at least one or two base modules 101, 102 coupled together and fastened between a head element or module 103 and an end element 104.
The head element or module 103, the two base modules 101, 102 and the end element 104 are mutually connected to form an assembly by means of fastening members of the tie-rod type 105.
Each base module 101, 102 is provided with a plurality of housings 106, each able to receive a respective solenoid valve 107, which can be fastened to the respective base module 101, 102 by means of screws.
Each solenoid valve 107 is of the spool type and, with reference to FIG. 2, it consists, for example, of a pair of “3/2” spool distributors, normally closed, housed in a same body 108.
Each solenoid valve 107 comprises:
a body 108, in which are obtained at least one feeding mouth 109, at least a first outlet mouth 110 and at least a first discharge mouth 111, at least a first spool-type slider 114, which is housed movably with alternate rectilinear motion in a seat obtained in the body 108 and it is configured to place selectively in fluid connection the at least one feeding mouth 109, the at least a first discharge mouth 111 and the at least a first outlet mouth 110,
at least a first actuation device of the first spool-type slider 114, which actuation device comprises, for example, at least a first electropilot 116 that commands a first actuating piston 117 integral with the first spool-type slider 114, and
at least a first repositioning device for example of the mechanical type and consisting of a first spring 120.
Each solenoid valve 107 can also comprise:
at least a second outlet mouth 112 and at least a second discharge mouth 113, at least a second spool-type slider 115, which is housed movably with alternate rectilinear motion in a seat obtained in the body 108 and it is configured to place selectively in fluid connection the at least one feeding mouth 109, the at least a second discharge mouth 113 and the at least a second outlet mouth 112,
at least a second actuation device for actuating the second spool-type slider 115, which actuation device comprises, for example, at least a second electropilot 118 which commands a second actuating piston 119 integral with the second spool-type slider 115, and
at least a second repositioning device for example of the mechanical type consisting of a second spring 121.
The feeding mouth 109, the first outlet mouth 110, the first discharge mouth 111, the second outlet mouth 112 and the second discharge mouth 113 of each solenoid valve 107 are all defined in the body 108 and are mutually aligned at the attachment face of the solenoid valve 107 to the respective housing 106 (the feeding mouth 109 is at the centre, at its sides are symmetrically positioned the first and the second outlet mouths 110 and 112, to the side of each of which is positioned respectively the first discharge mouth 111 and the second discharge mouth 113).
Between the body 108, the first spool-type slider 114 and the second spool-type slider 115 are interposed gaskets to provide a seal for the pressurised fluid.
With reference to FIG. 2, the first spool-type slider 114 has a portion with reduced diameter shaped so as to put the first outlet mouth 110 alternatively in communication with the first discharge mouth 111 and with the feeding mouth 109 following the movement of the first spool-type slider 114. Similarly, the second spool-type slider 115 has a portion with reduced diameter so shaped as to put the second outlet mouth 112 alternatively in communication with the second discharge mouth 113 and with the feeding mouth 109 following the movement of the second spool-type slider 115.
The base, or each base module 101, 102 comprises a plurality of housings 106 each of which is able to receive a respective said solenoid valve 107.
Each housing 106 comprises:
at least one feeding duct 122 adapted to be put in fluid connection with the feeding mouth 109 of the respective solenoid valve 107,
at least a first discharge duct 125 adapted to be put in fluid connection with the first discharge mouth 111 of the respective solenoid valve 107 and
at least a first outlet duct 123 adapted to be put in fluid connection with the first outlet mouth 110 of the respective solenoid valve 107.
Each housing 106 further comprise:
at least a second discharge duct 126 adapted to be put in fluid connection with the second discharge mouth 113 of the respective solenoid valve 107 and
at least a second outlet duct 124 able to be put in fluid communication with the second outlet mouth 112 of the respective solenoid valve 107.
The feeding duct 122, the first and the second outlet ducts 123 and 124 the first and second discharge ducts 125 and 126 of each housing 106 are all defined in the body of the respective base module 101, 102 with disposition and alignment corresponding to those of the respective mouths of the solenoid valves 107 coupleable therewith.
The feeding ducts 122 of the housings 106 are joined to or defined by a segment of a main feeding duct 122a obtained in the base, or in the base modules 101, 102, and common to all housings 106.
The first discharge ducts 125 of the housings 106 are joined to or defined by a segment of a first main discharge duct 125A obtained in the base or in the base modules 101, 102, and common to all housings 106.
The second discharge ducts 126 of the housings 106 are joined to or defined by a segment of a second main discharge duct 126A obtained in the base or in the base modules 101, 102, common to all housings 106.
The first outlet ducts 123 of the housings 106 each come out in a respective first delivery opening 123A which can be associated with a user U.
The second outlet ducts 124 of the housings 106 each come out in a respective second delivery opening 124A which can be associated with a user U.
The first outlet ducts 123 and the second outlet ducts 124 of the various housings 106 are distinct and separate from each other.
Each base module further comprises a respective electronic board 200 and electric connection means for connecting the electronic board with the devices for the electric or electro-pneumatic actuation and/or repositioning of each solenoid valve 107.
In the case shown in FIG. 2, the electronic board 200 is connected to the first electropilot 116 and to the second electropilot 118.
The head element or module 103, also called feeding module, comprises a body in which are obtained:
a first joining duct 127 that joins, at one end, with the at least one main feeding duct 122A of the base module 101, 102 directly coupled therewith and that, at the opposite end, can be joined with a source of pressurised fluid S; FIG. 1 shows the junction 127A schematically coupled to the source of pressurised fluid S;
a pair of second joining ducts 128 and 129 join, at one end, respectively with the first main discharge duct 125A and with the second main discharge duct 126A of the base module 101, 102 directly coupled therewith and, at the opposite end, they end in a common discharge opening 130 or alternatively in a respective separate discharge opening,
an electronic input module 131 provided with at least one input connector to receive command signals from outside the solenoid valve system and an output connector connectable to the corresponding input connector of the electronic board 200 of the base module 101, 102 directly connected thereto.
In FIG. 3, the mouths of each solenoid valve 107 are also indicated with the unified numbering shown in brackets, according to which: “1” designates the feeding mouth, i.e. the one that is usually fed with the pressurised fluid coming from the respective feeding duct obtained in the base module, “2” and “4” designate the outlet mouths, i.e. the ones that, usually, send the pressurised fluid to the users U connected to the respective outlet or delivery ducts obtained in the corresponding base module, “3” and “5” designate the discharge mouths, i.e. the mouths through which the fluid returning from the users is discharged.
In this figure, moreover, each solenoid valve 107 is designated simply with a rectangle, without showing the respective resting and working positions according to the unified symbology. The possible ducts for feeding and discharging air to the electropneumatic actuation/repositioning devices are also not indicated.
The shape of each solenoid valve 107, known in itself and of the type for the example of the one shown in FIG. 2, is described in general terms solely for the purpose of making the present description clearer.
It must be noted that each solenoid valve 107 could be of a type different from the one shown in FIG. 2; thus for example the solenoid valve 107 could be of one of the known types “3/2”, “5/2” or “5/3”, the first spool-type slider and the second spool-type slider could be integrated in a single spool-type slider, the actuation and repositioning devices could be different from those described above, for example they could both be electropneumatic (electropilot combined with actuating piston slaved thereto).
Some applications require the presence of a shut-off valve, or better yet of a shut-off solenoid valve that allows to make the circuit formed by the entire solenoid valve system independent from the general network or better yet from the source feeding pressurised fluid S.
Such a shut-off solenoid valve generally has two positions:                a closed position, in which it prevents the entry of the pressurised air coming from the feeding source S in the circuit formed by the solenoid valve system, putting the latter in discharge, and        a working position, in which it allows the entry of the compressed air coming from the feeding source S in the entire circuit formed by the solenoid valve system.        
Such a shut-off solenoid valve is particularly useful if maintenance work on the solenoid valve system becomes necessary.
According to the prior art, such a shut-off solenoid valve is positioned upstream of the solenoid valve system and it consists of a “3/2” shut-off solenoid valve which is joined and connected to the solenoid valve system upstream thereof.
According to another prior art solution, such a shut-off valve is integrated in the treatment unit for treating the pressurised air coming from the feeding source S; for example, it is integrated in a filter and pressure regulator unit which is connected upstream of the solenoid valve system.
Integrating a shut-off solenoid valve in the same solenoid valve system is also known. According to this prior art, the shut-off solenoid valve is “3/2” and it is connected to an auxiliary base module, which is dedicated thereto and it is interposed between the base and the head module of the solenoid valve system. If the base is divided into different sections operating at different pressures and each provided with a respective inlet (feeding and discharge) module, each section is provided with a respective “3/2” shut-off solenoid valve which is connected to an auxiliary base module dedicated thereto and interposed between the base section and the respective head (feeding and inlet) module.
Such a known solution is schematically shown in FIG. 4, which reproduces the diagram of FIG. 3 with the addition of the shut-off solenoid valve 300 and of the respective auxiliary base module 301 dedicated thereto. It is noted that the shut-off solenoid valve 300 is positioned upstream of the base 101, 102 of solenoid valves 107 so as to be able to make the circuit downstream thereof independent of the feeding source S of compressed air, fully putting it in discharge.
Such a known solution makes it possible to reduce the overall dimensions and to simplify the pneumatic connections with respect to the other known solutions, described above. It also makes it possible to command the shut-off solenoid valve 300 through the same inlet module, be it with multipolar cable or with serial connection, of the solenoid valve system.
However, such a known solution has some drawbacks.
A first drawback is that it requires the construction of an auxiliary base module dedicated thereto. As is readily apparent just from the diagram of FIG. 4, such an auxiliary base module differs from the base modules 101, 102 of the solenoid valve system at least with regard to the shape of the main feeding duct. In this auxiliary base module 301, the main feeding duct necessarily consists of two separate branches: a first branch 322A which connects the outlet mouth (2) of the shut-off solenoid valve 300 to the main feeding duct 122A of the subsequent base modules 101, 102 and a second branch 322B that connects the feeding mouth (1) of the shut-off solenoid valve 300 to the first joining duct 127 of the head module 103 that is connected at the inlet with the feeding source S.
As is immediately understandable for the person skilled in the art, the base modules 101, 102 of the solenoid valve system instead have a single main feeding duct (designated with the numeral 122A in FIG. 3) passing through them and which is common to all housings 106, or that serves each housing 106.
Only in this way, when the shut-off solenoid valve 300 is in resting position the entire circuit downstream thereof, also comprising the main feeding duct 122A, is in discharge; when, instead, the shut-off solenoid valve 300 is in the working position, the compressed air fed by the feeding source S into the head module 103 is fed to the entire circuit downstream of the shut-off solenoid valve 300.
The need to have an auxiliary base module different from the base modules of the solenoid valve system entails, obviously, higher production costs, a complication of the mounting and dismounting operations and in any case greater overall dimensions of the solenoid valve system.
An additional drawback of this known solution is that the shut-off solenoid valve can be mounted only in fixed position between the head module and the base of the solenoid valve system.
In addition, it has to be dimensioned according to the maximum flow rate of the air necessary for the operation of the solenoid valve system.